1. Field of the Invention
The present invention relates to technology for printing by forming dots on a printing medium while performing a main scan, and specifically relates to technology for printing images for which there are two types of areas, color areas and monochromatic areas, in the sub-scan direction.
2. Description of the Related Art
In recent years, as computer output devices, there has been a broad popularization of color printers of the type that eject several colors of ink from a head. Among this type of color printer, there are printers that print an image by forming dots on a printing medium by ejecting ink drops from a nozzle while performing a main scan.
Also, there are printing devices that are equipped with a higher number of nozzles that eject only black ink than those for other colored inks. For that kind of printing device, when printing color data, color printing is done using the same number of nozzles for each color. Only the same number of nozzles as the number of nozzles for each color is used for the black nozzles. Then, when printing data represent a monochromatic image, the monochromatic printing is performed at high speed using all of the black nozzles.
However, with the printing device noted above, when within the printed image there are two types of areas, monochromatic areas that use only black ink, and color areas, there is the problem that printing cannot be performed efficiently.
Accordingly, an object of the present invention is to efficiently print images for which two types of areas, color areas and monochromatic areas, exist in the sub-scan direction.
To attain at least part of the above and other related objects of the present invention, there is provided a printing apparatus that prints images in a monochromatic area on a printing medium with an achromatic ink alone, and in a color area with chromatic inks, by ejecting ink drops from a nozzle to deposit the ink drops on the printing medium to form dots.
This printing apparatus comprises a printing head, a main scan drive unit, a sub-scan drive unit and a control unit. The printing head has a plurality of single chromatic nozzle groups for ejecting mutually different chromatic inks and an achromatic nozzle group for ejecting achromatic ink. The plurality of single chromatic nozzle groups each consists of plurality of nozzles. The achromatic nozzle group consists of a greater number of nozzles than each of the single chromatic nozzle groups. The main scan drive unit moves at least one of the printing head and the printing medium to perform main scanning. The sub-scan drive unit moves at least one of the printing head and the printing medium in a direction that intersects a main scanning direction to perform sub-scanning. The control unit controls the printing head, the main scan drive unit and the sub-scan drive unit.
The printing device performs the following procedure when the lower edge of a monochromatic area and the upper edge of a color area come into contact with each other. Regular monochromatic mode printing is executed whereby sub-scans are performed in a first sub-scan mode, and dots are formed along the main scan lines in the monochromatic area. Lower-edge monochromatic mode printing is executed whereby sub-scans are performed in a second sub-scan mode in which a maximum sub-scan feed increment is less than a maximum sub-scan feed increment of the first sub-scan mode, and dots are formed along the main scan lines in the monochromatic area in the vicinity of a border with the color area. Upper-edge color mode printing is executed whereby sub-scans are performed in a third sub-scan mode, and dots are formed along the main scan lines in the color area in the vicinity of the border with the monochromatic area. Regular color mode printing is executed whereby sub-scans are performed in a fourth sub-scan mode in which a maximum sub-scan feed increment is greater than a maximum sub-scan feed increment of the third sub-scan mode, and dots are formed along the main scan lines in the color area. Adopting this arrangement will result in a smooth transfer from the printing of a monochromatic area to the printing of a color area.
When the nozzles of the single chromatic nozzle groups are arranged at a nozzle pitch kcxc3x97D, and the nozzles of the achromatic nozzle group are arranged at a nozzle pitch kmxc3x97D, the printing procedure may be preferably performed as follows. Specifically, the printing in each of the regular monochromatic mode printing, the lower-edge monochromatic mode printing, the upper-edge color mode printing and the regular color mode printing may be interlaced printing. Note that kc is an integer of 2 or greater, D is a pitch of main scan lines, and km is an integer of 2 or greater. Adopting this arrangement makes it possible to improve the quality of printed results.
The following approach should preferably be adopted when the single chromatic nozzle groups have mutually equal numbers of Nc nozzles (where Nc is an integer of 2 or greater) arranged at a nozzle pitch kcxc3x97D (where kc is an integer of 2 or greater), which is kc times the pitch D of the main scan lines, and the achromatic nozzle group has Nm nozzles (where Nm is an integer grate than Nc) arranged at a nozzle pitch kmxc3x97D (where km is an integer equal to the inverse of the natural portion of kc).
In the regular monochromatic mode printing, monochromatic mode main scans may be preferably performed alternately with the sub-scans in which the achromatic nozzle group is used but the single chromatic nozzle groups are not used. In the lower-edge monochromatic mode printing, the monochromatic mode main scans may be preferably performed at least (kmxe2x88x921) times alternately with the sub-scans. In the upper-edge color mode printing, color mode main scans may be preferably performed at least (kcxe2x88x921) times alternately with sub-scans in which the plurality of single chromatic nozzle groups and specific achromatic nozzle group are used. The specific achromatic nozzle group may be selected from the achromatic nozzle group and consist of Nc nozzles arranged at a nozzle pitch kcxc3x97D. In the regular color mode printing, color mode main scans may be performed alternately with the sub-scans. Adopting this arrangement makes it possible to record images along each main scan line with no gaps between the lines, and to transfer from the printing of monochromatic area to the printing of color area.
It is preferable that the plurality of single chromatic nozzle groups comprise a cyan nozzle group for ejecting a cyan ink, a magenta nozzle group for ejecting a magenta ink and a yellow nozzle group for ejecting a yellow ink. The cyan nozzle group, magenta nozzle group, and yellow nozzle group should preferably be disposed in the order indicated in the direction of sub-scanning. The achromatic nozzle group should preferably be equipped with Ncxc3x973 nozzles arranged at a nozzle pitch kcxc3x97D and be disposed in the area for accommodating the nozzles cyan nozzle group, magenta nozzle group, and yellow nozzle group. The specific achromatic nozzle group should preferably be disposed in the area for accommodating the nozzles of the cyan nozzle group in the direction of sub-scanning. Adopting this arrangement makes it less likely that inks will bleed into each other, because the cyan, magenta, and yellow inks ejected within the same pixel are deposited onto this pixel during different main scans. It is also possible to arrange the nozzles of the achromatic nozzle groups in an optimal manner without unduly increasing the size of the print head in the direction of sub-scanning.
When the nozzles of the achromatic nozzle group are arranged at a nozzle pitch kmxc3x97D, where km is an integer of 2 or greater, the sub-scans should preferably be performed (kmxe2x88x921) times in lower-edge monochromatic mode printing. Adopting this arrangement makes it possible to record images along each main scan line with no gaps between the lines in the monochromatic area in the vicinity of the border with the color area.
When the nozzles of the single chromatic nozzle groups are arranged at a nozzle pitch kcxc3x97D, where kc is an integer of 2 or greater, the sub-scans should preferably be performed (kcxe2x88x921) times in upper-edge color mode printing. Adopting this arrangement makes it possible to record images along each main scan line with no gaps between the lines in the color area in the vicinity of the border with the monochromatic area.
When a topmost nozzle of the plurality of single chromatic nozzle groups is in a position upside of a border of the monochromatic area and the color area, upper-edge color mode printing should preferably be started. Adopting this arrangement makes it possible to record images along the main scan lines of the upper-edge portion of a color area with no gaps between the lines.
After lower-edge monochromatic mode printing and before upper-edge color mode printing, the sub-scan should preferably be performed such that the print head is placed at a specific position near an upper edge of the color area when a distance between the print head and the upper edge of the color area at the end of lower-edge monochromatic mode printing is less than a specific value. Adopting this arrangement makes it possible to print images in an efficient manner without making unnecessary sub-scans.
The sub-scan should preferably be performed such that the print head is put to a first relative position in relation to the printing medium from a second relative position at which the print head is located at the end of lower-edge monochromatic mode printing, when the second relative position falls outside a permissible range of the first relative position. The first relative position is defined to be a position such that when the print head is positioned at the first relative position and upper-edge color mode printing is performed starting from the first relative position, the main scan lines can be recorded without any gaps all the way from the upper edge of the color area. Adopting this arrangement makes it possible to record images along the main scan lines of the upper-edge portion of a color area with no gaps between the lines, to dispense with unnecessary sub-scans, and to print images in an efficient manner.
It is preferable that the printing procedure in regular monochromatic mode printing proceeds to lower-edge monochromatic mode printing without position adjusting feed in case as follows. The case is that a first relative position of the print head in relation to the printing medium lies below a second relative position. The first relative position is defined to be a position reached by the print head when a subsequent sub-scan in the first sub-scan mode and all the sub-scans to be performed during lower-edge monochromatic mode printing are performed. The second relative position is defined to be a position such that when the print head is positioned at the second relative position and upper-edge color mode printing is performed starting from the second relative position, the main scan lines can be recorded without any gaps all the way from the upper edge of the color area. Adopting this arrangement makes it possible to transfer from the printing of monochromatic area to the printing of color area without performing sub-scanning in the reverse direction.
When the nozzles of the achromatic nozzle group are arranged at a nozzle pitch kmxc3x97D, the first sub-scan mode in the regular monochromatic printing mode should preferably be a mode for carrying out a constant sub-scan feeding with constant feed increments of p1xc3x97D. Note that km is an integer of 2 or greater, D is a pitch of main scan lines and p1 is an integer constituting a prime with km.
When the nozzles of the single chromatic nozzle groups are arranged at a nozzle pitch kcxc3x97D, the fourth sub-scan mode in regular color mode printing should preferably be a mode for carrying out a constant sub-scan feeding with constant feed increments of q1xc3x97D. Note that kc is an integer of 2 or greater and D is a pitch of main scan lines and q1 is an integer constituting a prime with kc.
When the nozzles of the achromatic nozzle group are arranged at a nozzle pitch kmxc3x97D, the second sub-scan mode in lower-edge monochromatic mode printing should preferably be a mode for carrying out a constant sub-scan feeding with constant feed increments of p2xc3x97D. Note that km is an integer of 2 or greater, D is a pitch of main scan lines and p2 is an integer constituting a prime with km.
When the nozzles of the single chromatic nozzle groups are arranged at a nozzle pitch kcxc3x97D, the third sub-scan mode in upper-edge color mode printing should preferably be a mode for carrying out a constant sub-scan feeding with constant feed increments of q2xc3x97D. Note that kc is an integer of 2 or greater, D is a pitch of main scan lines and q2 is an integer constituting a prime with kc.
Adopting these arrangements makes it possible to record images along the main scan lines through a simple procedure and with no gaps between the lines by following individual sub-scan modes.
In the third sub-scan mode in upper-edge color mode printing, q2 should preferably be 1. Adopting this arrangement makes it possible to reduce the number of main scans performed during upper-edge color mode printing. It is also possible to set the value of p2 to 1 in the second sub-scan mode for performing lower-edge monochromatic mode printing.
The first sub-scan mode in regular monochromatic mode printing may be a mode for carrying out a non-constant sub-scan feeding that includes performing repeated combinations of sub-scans in variable feed increments. The fourth sub-scan mode in regular color mode printing may be a mode for carrying out a non-constant sub-scan feeding that includes performing repeated combinations of sub-scans in variable feed increments. Adopting this arrangement makes it possible to further improve the quality of printing results in each sub-scan mode. The second sub-scan mode for performing lower-edge monochromatic mode printing can also be made into a mode designed for non-constant sub-scan feeding, as can the third sub-scan mode for performing upper-edge color mode printing.
The following arrangement should preferably be adopted when the lower edge of a color area and the upper edge of a monochromatic area are in contact with each other. Regular color mode printing is executed whereby sub-scans are performed in a first sub-scan mode, and dots are formed along the main scan lines in the color area. Lower-edge color mode printing is executed whereby sub-scans are performed in a second sub-scan mode in which a maximum sub-scan feed increment is less than a maximum sub-scan feed increment of the first sub-scan mode, and dots are formed along the main scan lines in the color area in the vicinity of the border with the monochromatic area. Upper-edge monochromatic mode printing is executed whereby sub-scans are performed in a third sub-scan mode, and dots are formed along the main scan lines in the monochromatic area in the vicinity of a border with the color area. Regular monochromatic mode printing is executed whereby sub-scans are performed in a fourth sub-scan mode in which a maximum sub-scan feed increment is greater than a maximum sub-scan feed increment of the third sub-scan mode, and dots are formed along the main scan lines in the monochromatic area. Adopting this arrangement will result in a smooth transfer from the printing of a color area to the printing of a monochromatic area.
When the nozzles of the single chromatic nozzle groups are arranged at a nozzle pitch kcxc3x97D, and the nozzles of the achromatic nozzle group are arranged at a nozzle pitch kmxc3x97D, the printing procedure may be preferably performed as follows. Specifically, in the regular color mode printing, the lower-edge color mode printing, the upper-edge monochromatic mode printing and the regular monochromatic mode printing, interlaced printing may be preferably executed. Note that kc is an integer of 2 or greater, D is a pitch of main scan lines and km is an integer of 2 or greater. Adopting this arrangement makes it possible to improve the quality of printed results.
The following approach should preferably be adopted when the single chromatic nozzle groups have mutually equal numbers of Nc nozzles arranged at a nozzle pitch kcxc3x97D, and the achromatic nozzle group has Nm nozzles arranged at a nozzle pitch kmxc3x97D. Note that Nc is an integer of 2 or greater, kc is an integer of 2 or greater, D is a pitch of main scan lines, Nm is an integer grater than Nc, km is an integer equal to kc/J and J is a positive integer.
In regular color mode printing, color mode main scans are performed alternately with the sub-scans in which the plurality of single chromatic nozzle groups and specific achromatic nozzle group are used. The specific achromatic nozzle group is selected from the achromatic nozzle group and consists of Nc nozzles arranged at a nozzle pitch kcxc3x97D. In lower-edge color mode printing, the color mode main scans are performed at least (kmxe2x88x921) times alternately with the sub-scans. In upper-edge monochromatic mode printing, monochromatic mode main scans are performed at least (kcxe2x88x921) times alternately with sub-scans in which the achromatic nozzle group are used but the single chromatic nozzle groups are not used. In regular monochromatic mode printing, the monochromatic mode main scans are performed alternately with the sub-scans. Adopting this arrangement makes it possible to record images along each main scan line with no gaps between the lines, and to transfer from the printing of a color area to the printing of a monochromatic area.
When the nozzles of the single chromatic nozzle groups are arranged at a nozzle pitch kcxc3x97D, where kc is an integer of 2 or greater, the sub-scans should preferably be performed (kcxe2x88x921) times in lower-edge color mode printing. Adopting this arrangement makes it possible to record images along each main scan line with no gaps between the lines in the color area in the vicinity of the border with the monochromatic area.
When the nozzles of the achromatic nozzle group are arranged at a nozzle pitch kmxc3x97D, where km is an integer of 2 or greater, the sub-scans should preferably be performed (kmxe2x88x921) times in upper-edge monochromatic mode printing. Adopting this arrangement makes it possible to record images along each main scan line with no gaps between the lines in the monochromatic area in the vicinity of the border with the color area.
When a topmost nozzle of the achromatic nozzle group is in a position upside of a border of the color area and the monochromatic area, upper-edge monochromatic mode printing should preferably be started. Adopting this arrangement makes it possible to record images along the main scan lines of the upper-edge portion of a monochromatic area with no gaps between the lines.
It is preferable that the sub-scan is performed such that the print head is placed at a specific position near an upper edge of the monochromatic area when a distance between the print head and the upper edge of the monochromatic area at the end of lower-edge color mode printing is less than a specific value. Adopting this arrangement makes it possible to print images in an efficient manner without making unnecessary sub-scans.
The sub-scan of the position adjusting feed may preferably performed such that the print head is put to a first relative position in relation to the printing medium from a second relative position at which the print head is located at the end of lower-edge color mode printing, when the second relative position falls outside a permissible range of the first relative position. The first relative position is defined to be a position such that when the print head is positioned at the first relative position and upper-edge monochromatic mode printing is performed starting from the first relative position, the main scan lines can be recorded without any gaps all the way makes it possible to record images along the main scan lines of the upper-edge portion of a monochromatic area with no gaps between the lines, to dispense with unnecessary sub-scans, and to print images in an efficient manner.
In the regular color mode printing, it is preferable that the printing procedure proceeds to lower-edge color mode printing without position adjusting feed in the case as follows. The case is that a first relative position of the print head in relation to the printing medium lies below a second relative position. The first relative position is defined to be a position reached by the print head when a subsequent sub-scan in the first sub-scan mode and all the sub-scans to be performed during lower-edge color mode printing are performed. The second relative position is defined to be a position such that when the print head is positioned at the second relative position and upper-edge monochromatic mode printing is performed starting from the second relative position, the main scan lines can be recorded without any gaps all the way from the upper edge of the monochromatic area. Adopting this arrangement makes it possible to transfer from the printing of color area to the printing of monochromatic area without performing sub-scanning in the reverse direction. Each sub-scan mode can be made into a mode designed for constant sub-scan feeding. A mode designed for non-constant sub-scan feeding can also be obtained.
In case that the nozzles of the single chromatic nozzle groups are arranged at a nozzle pitch kcxc3x97D, the second sub-scan mode in lower-edge color mode printing should preferably be a mode for carrying out a constant sub-scan feeding with constant feed increments of q2xc3x97D. Note that kc is an integer of 2 or greater, D is a pitch of main scan lines and q2 is an integer constituting a prime with kc.
When the nozzles of the achromatic nozzle group are arranged at a nozzle pitch kmxc3x97D, the third sub-scan mode in upper-edge monochromatic mode printing should preferably be a mode for carrying out a constant sub-scan feeding with constant feed increments of p2xc3x97D. Note that km is an integer of 2 or greater, D is a pitch of main scan lines and p2 is an integer constituting a prime with km.
Adopting these arrangements makes it possible to record images along the main scan lines through a simple procedure and with no gaps between the lines by following individual sub-scan modes.
In the second sub-scan mode in lower-edge color mode printing, q2 should preferably be 1. Adopting this arrangement makes it possible to reduce the number of main scans performed during lower-edge color mode printing. It is also possible to set the value of p2 to 1 in the third sub-scan mode for performing upper-edge monochromatic mode printing.
The present invention can be realized in a variety of embodiments such as those shown below.
(1) Printing method and printing control method
(2) Printing apparatus and printing control apparatus
(3) A computer program for realizing the aforementioned device or method
(4) A recording medium on which is recorded a computer program for realizing the aforementioned device or method
(5) Data signals implemented within carrier waves including a computer program for realizing the aforementioned device or method
These and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with the accompanying drawings.